A precise description of protein dynamics is fundamental to an understanding of the relationship between structure and function for such diverse problems as: the binding of ligands to proteins, the catalytic activity of enzymes and the transport of ions through membranes. Computer simulations of protein dynamics constitute the most detailed theoretical approach available for studying the internal motions of proteins. The goals of this proposal are threefold: (1) to continue our major effort directed towards strengthening the connections between computer simulations and experimental probes of protein dynamics, (2) to explore the relationship between conformational flexibility and protein structure and function, and (3) to develop new and more accurate simulation techniques. The proteins currently being studied using simulation methods in our group include myoglobin, ovomucoid proteinase inhibitors and the complex of Rhizopus chinensis carboxyl proteinase with pepstatin. Additional model peptide systems are also being investigated.